Thomas Moore, cohead of the energy M&A practice at Dewey & LeBoeuf in Houston, is advising UEG on the deal, along with associates Catherine Harlan and Dina Yin. In a statement, the firm noted the importance of the deal for UEG, which does not have in-house counsel.

"UEG is the first Chinese company not owned by the state to have made a major acquisition outside China," Moore said. "It will be very interesting to see whether this is the start of a trend where investor-owned Chinese energy companies pursue the same aggressive acquisition strategy around the world as that pursued by state-owned companies."